The original XS850 Suspension was pretty good for its day: air adjustable forks, large diameter forks and dual rear shocks.
Since my bike needs alot of love and care, it's going to get more that it ever should...
I was interested in a swap done to another triple:
Henrik put a Triumph Spirit fork on the front of his XS750 cafe racer. nice eh?
I got a deal on a set of 2006 GSXR forks - which have been swapped on many, many, many bikes. (but not XS's as far as I know).
As a bonus, now I can add new calipers and probably a GSXR/hayabusa front wheel with 300+mm rotors.
The GSXR uses a pair of bearings that are the same dimension for both the upper and lower bearings.
The Yamaha uses two different sizes of bearing for the upper and lower. Steve's bearing reference has GSXR bearing specs for reference.
According to Steve, "The microfiche lists the Steering Stem bearings as 30mm ID X 55mm OD X 17mm Wide."
I measured both forks and stearing neck bearing surfaces on the Yamaha to get started. (With the lower race still stuck in the yamaha head)
The GSXR upper is just a hair smaller than 30mm, allowing you to slide a 30mm bearing past and seat it down below.
So, we'll need a 30x47x15 for the upper and a 30x55x17 for the lower.
I can probably use a stock XS850 bearing on the lower and a custom bearing up top.
It appears that a 30x47 bearing doesn't exist, but some people turn down a 25x48 bearing race.
One person who makes them is Zoran at TWF racing.
In addition to the bearing from Zoran, I purchased new upper seals, a lower bearing, and washers from the dealer.
Since my second hand forks didn't include the castle or crown nuts, I picked them up off ebay for around $10.
Those three nuts are $60 from the dealer, so it's worth the effort to ebay for them. (there are two sizes of crown nut, so watch out)